Fuel Gauge

Rebel-Chevy · Post by **Rebel-Chevy** » Sun Oct 28, 2007 1:40 pm

SO tonight when i was ripping my radio out of the dash i started the truck and the "Low Fuel" light was on, i looked back a min later and it was a little below a quarter. I looked again and seen it move a bit. The truck was on level ground and not moving... anyone get any ideas?

Post by **HenryJ** » Sun Oct 28, 2007 1:52 pm

Get ready for a new fuel pump module.

Rebel-Chevy · Post by **Rebel-Chevy** » Sun Oct 28, 2007 2:03 pm

really? how much do they run new?

Post by **HenryJ** » Sun Oct 28, 2007 2:45 pm

$200-$400

Rebel-Chevy · Post by **Rebel-Chevy** » Sun Oct 28, 2007 2:48 pm

gotta love junk yards

Post by **HenryJ** » Sun Oct 28, 2007 2:50 pm

They won't be any better than yours. Buy new AC Delco, or plan to do this again real soon.

You can try a bottle if cleaner to see if that helps. If you have been doing that every other oil change as recommended, it is too late and the fingers are worn off already, it is not just coated with deposits.

Rebel-Chevy · Post by **Rebel-Chevy** » Sun Oct 28, 2007 2:52 pm

what kind of cleaner?

Post by **HenryJ** » Sun Oct 28, 2007 2:53 pm

Injector cleaner. I use the cheap stuff. Valvoline synthetic.

Rebel-Chevy · Post by **Rebel-Chevy** » Sun Oct 28, 2007 2:55 pm

alright, and what happens if you put this for for a while? just fuel gauge wont work?

Post by **HenryJ** » Sun Oct 28, 2007 3:03 pm

Gas gauge problems

HenryJ wrote:The fuel sender has contacts that look like tiny fingers. They rub across a printed board and wear. Below half a tank of fuel they are in the "airspace". When the tank is full they are immersed in liquid. This tends to alter the symptoms.

In my experience the senders tend to wear out in the 100, 000-140,000 mile range , or around five years of use. This can vary depending upon how the assembly has been treated. Those who maintain the fuel tank above half a tank , and use high quality fuel seem to have the module last longer. Invariably they all seem to go by 150,000 miles. Some may have the fuel pump fail, others the gauge sender. I like to change the complete assembly when the problems become consistent. The fuel pump failure can be instantaneous and with out warning. Some times it may have the foot valve leakage as a symptom. This shows up as needing to crank over several times on a cold start. Another indicator can be poor performance from inadequate fuel pressure.

Plan on spending $200-$300 for the fuel pump module assembly. I like to use OEM ACDelco parts.

Yeah! another problem.... Erratic Fuel Guage , Stalling

HenryJ wrote:Here is a good example -

This one is from a 2000 fullsize with 99,000 miles. Ours is similar , and this one will show the problems. This one was erratic, and sometimes it did not work at all. Eventually it quit all together.
Here is a close-up-

At the top you can see the float rod. It serves as the pivot point and with time wears. This lets the assembly get loose. Below that you can see the two contacts with their tiny fingers. These ride against the printed circuit board. The tips eventually wear out and break off, or the printed contacts on the bard wear off.
Another thing to note here is that the plastic starts out white. Additives and contaminants stain it brown. This coating does not help promote good contact.
Now you can see where the problems lie. Another thing to bring up here is the use of additives that coat the components. This is done to prevent the adhesion of deposits. The problem is that while insulating the formation of deposits it may also insulate the contacts preventing good contact as well?
Quite some time ago I read an article about a brand of fuel that uses an additive that coats to prevent the formation of deposits. GM was in the process of investigating if there was a relationship between this and the sticking poppets plaguing the early SFI engines. I never did read or hear more. They solved it by upgrading the spider and therefore eliminating the problem area.
Personally I think there may still be a link to the fuel sender problems. Perhaps the coating traps debris creating an abrasive surface leading to premature wear? Or the coatings interfere with proper contact? I do not have THE answer. I do avoid some brands of fuel and additives though. superstitious? Maybe?

Rebel-Chevy · Post by **Rebel-Chevy** » Sun Oct 28, 2007 3:09 pm

Great so now i need to spend money on a new FPM, New speakers(i think), New rotors or cut them down, probbly new from axles, and tires.

Post by **HenryJ** » Sun Oct 28, 2007 3:14 pm

Then you have a new truck, right? Look at it this way $1000 per year in maintaining a vehicle is pretty cheap. That is outside normal fluids and other consumables.

Rebel-Chevy · Post by **Rebel-Chevy** » Sun Oct 28, 2007 3:16 pm

i bought the truck for $1,400 two weeks ago so this really sucks
but it does have 200,000

F9K9 · Post by **F9K9** » Sun Oct 28, 2007 3:50 pm

Rebel-Chevy wrote:i bought the truck for $1,400 two weeks ago so this really sucks
but it does have 200,000

Screw the gauge and go by the trip odometer! Fill it up at 150 miles and suck it up a drive on! They were not right when they drove off of the lot and some members have fought hard to have the issue corrected. Ain't no fix for it. You have to deal with a few quirks with any vehicle, let alone one with 200K+.

Rebel-Chevy · Post by **Rebel-Chevy** » Sun Oct 28, 2007 3:51 pm

haha i like your idea

Post by **HenryJ** » Sun Oct 28, 2007 3:52 pm

That'll work. You can wait for the fuel pump to quit and fix it then.

F9K9 · Post by **F9K9** » Sun Oct 28, 2007 4:00 pm

HenryJ wrote:That'll work. You can wait for the fuel pump to quit and fix it then.

You have a valid point but, I suspect that he'll be close to a friend or relative. My gauge didn't work for three of the seven years I owned my '97 ZR2. Hit places like DC and the windy city without failure. That was with my "LUCK"!

Rebel-Chevy · Post by **Rebel-Chevy** » Sun Oct 28, 2007 4:31 pm

so if i keep it above a half tank it will work?

F9K9 · Post by **F9K9** » Sun Oct 28, 2007 5:42 pm

Rebel-Chevy wrote:so if i keep it above a half tank it will work?

Can't promise you that. Most of the CC fuel gauges act nuts around 1/4 tank. They may be at 1/4 when you get home and the next morning when you fire it up it will show less than 1/4 and your low fuel warning light will be on. There is no rhyme nor reason to them. Your best bet is to fill up at 1/2 empty and use your trip odometer religiously. A plus to this procedure, according to HenryJ, is that it helps to keep your fuel pump cooler when the tank is on the full side. A cooler fuel pump means longer life. At 200K we need every little bit of help that we can get

Rebel-Chevy · Post by **Rebel-Chevy** » Mon Oct 29, 2007 9:50 am

is it worth just getting a new fuel pump?

killian96ss · Post by **killian96ss** » Mon Oct 29, 2007 10:12 am

Rebel-Chevy wrote:is it worth just getting a new fuel pump?

No, that won't fix anything, unless you are having low pressure or bleed down problems.

As far as I know there is no "real" fix for this problem.

I've had the computer re-flashed 2x with the updated calibration and a new sending unit installed with no change.

Just keep the tank above 1/3 and avoid using Chevron gas with Techron.

I only use Shell and 76.

A little Marvelous Mystery oil in the gas also seems to help the sending unit read more accurately, probably becacaue of the extra lubrication.

Steve

Rebel-Chevy · Post by **Rebel-Chevy** » Mon Oct 29, 2007 10:18 am

today i found out that my one buddy that had a silverado had the same problem, they changed the FPM and it was fine again. but i'm going probbly going to pick up some injector cleaner, Marvelous Mystery Oil, and my one buddy said there is this stuff that is called "CSR Restore" or "CLR Restore" in a silver can, do you know anything about that?

doughboy5499 · Post by **doughboy5499** » Mon Oct 29, 2007 12:20 pm

I went a yr and a half with no gas guage. It sucks cause everytime you get gas you gotta fill it up all the way or sit and do some calculations to see how much gas you used and how much you got left.

border man · Post by **border man** » Mon Mar 31, 2008 8:15 pm

Well after almost three months of being stuck on full, I'm going to bite the bullet and spend the money on a new fuel pump. Along with the bad gauge, my pump has been making a whinning noise that has only gotten louder over past year. It is really LOUD! now, and I'm afraid it will leave me stranded soon. Question for the experts here? RockAuto lists a Delphi pump and an AcDelco one. Isn't Delphi the OEM supplier for GM? 2, is it all one unit? and 3, anybody ever do business with these guys? and do I have the right part no. for a 2000?
http://store.getgmparts.com/fg0248.html

roadrunner · Post by **roadrunner** » Mon Mar 31, 2008 8:26 pm

Just a suggestion but you might want to try www.pricegrabber.com to perhaps find a better price. I did on my MAF sensor and came up with a reman Cardone for $92.75 including free shipping and no core chg. Just type in the # of the part and check out some of the sites that come up. Try both the GM # and the aftermarket # as well. Might also try the Delco # if you know it.

PATRICKH · Post by **PATRICKH** » Thu Apr 03, 2008 5:25 am

idid the same thing f9k9 did. I used my trip odometer and filled up at 150-175 miles. Until I had to replace the fuel pump. Ypu'll notice some hard start problems about a week before it goes. (I did anyway)

roadrunner · Post by **roadrunner** » Thu May 22, 2008 7:48 pm

Well, my guage finally died the other day too. Driving on trip meter now and will continue until pump dies or I get too p***d off to continue to use that method.